Es'hail-2 Transverter

Kleiner,

I will be _very_ interested in that dual band feed - it is the missing link in my current plan, and would save me a dish!

73s

Iain

Do you think it would be feasible to construct a 13cm feed that would fit around a standard TV LNB? I will use my TV dish with a PLL LNB for receive (it is mounted on a H-to-H motor) and I currently have an LNB that has (with the plastic removed) a neck of 20mm and a horn of 50mm diameter. That could be a bit large to accomodate your 13cm feed, isn't it? Another difficulty is that the horn cannot be removed so it will be tricky to get the 13cm feed fitted around the neck.

Peter, an alternative could be to mill off the horn part of
the LNB and use 24/22 Ms or Cu pipe/tube in conjunction
with your patch feed.

Thus omitting the SMA-connector and bottom plate in your
current 10 GHz-contraption.

Quote from kleiner Peter

What we need is a slim LNB (picture 3) with a PLL (and TCXO, OCXO or an external referenz). But until now I could not find such an LNB.

It looks like the technology for LNBs has changed. I ordered a couple of PLL LNBs in China and received a box that was not even mentioning PLL on it. I mailed back the sender that I got an ordinary LNB while the website said "PLL" and the reply was that it really was PLL. I opened one and he is right, it has a 25 MHz crystal and no DRO.

So maybe I try to order some slim LNBs and see if they happen to be PLL as well. It could well be that the cost for manufacturing a PLL LNB is now below a DRO type and they just silently switched over. My LNBs were only 7 euro each...

Mix2g4 vs Lg-lab any comment ? Hard choise.... IW0EFI

We (Phase 4 Ground) have a dual band feed design that we're 3D printing and testing for P4A that might be worth considering.

It's a helical over a circular waveguide. I'll post more as soon as I can. We were asked about it after we published the P4B dual band feed.

I´ve prepared a PLL LNB. I exchanged the original crystal quartz with a custom crystal quartz manufactured by Firma Quartz Technik, Daun / Eiffel. f = 23.58974 MHz.

LOF/L now 9,200 GHz. Test with wideband BADR signal is successful.

I try to receive the narrowband downlink with my FT-736 1,2 GHz modul on the downmixed 1289,8 MHz ZF frequency.

Is it also a bit more stable than the standard crystal?

I have tested with an unmodified standard PLL LNB and in steady weather and not around sunrise/sunset it is bearable, but realistically you'll always have to have your hand on the dial for SSB.

Of course it is possible to lock it to a GPS reference, but I also consider some form of automatic locking (at the IF frequency) to the beacon.

Yes, you are right. These are also my fears.

I´ve bought the best available in terms of temperature and frequency stability. Is it enough? We will see...

In the worst case, I have to improve with a heating pill .....

See my solution:

http://www.floroy.de/db8tf/hail2.htm

VY DB8TF

Quote from DB8TF

See my solution:

Yes it should be possible to solve it using locking, however what we need (in the software) is some possibility to lock on the beacon and then tune to another frequency where the locking that tracks the beacon also makes the tuned qrg track in the same way. I don't think that is already available in one of the SDR programs, but it probably will be in the future when lots of people face this issue and some competent SDR programmer picks it up.

A (very) good crystal ('especially cut for you') has a precision in the range of
0.5 ppm (variation in temperature(s) not included).

So, for these PLL-LNB's with a crystal of (mostly) either 25 or 27 MHz, let's take

26 MHz as mean frequency, the frequency will be off (in worst case)
0.5 * 26 --> +/- 13 Hz (a range of 26 Hz)

The LNB 1st LO is (often) 9750 MHz, divided by 26 MHz = 375 * 13 = +/- 4.875,

say ... +/- 5 kHz off and/or 'wobbly' in worst cases (over time).

So, my opinion is that a single crystal will not be sufficient for narrow band
operation. (Your .. all .. mileage(s) may (of course) vary)

I will use this UPconverter for NB transponder and WB transponder ....

Input range: 100MHz .... 1300MHz
Version1..... -15dBm
Version2.... +10dBm

Output range: 2365 ..... 2500MHz , >200mW output analog and digital

Technical report.... https://www.oe7forum.at/viewto…f=7&t=284&start=180#p2321